Speed, Distance & Time Calculator
Calculate speed, distance, or time when you know the other two.
Supports km/h, mph, m/s, and knots — useful for driving, running, cycling, and sailing.
Speed, velocity, and distance are the three pillars of kinematics — the branch of physics that describes motion. These three quantities are bound by a set of simple but powerful formulas that apply everywhere from a Sunday drive to spacecraft navigation.
The three core formulas:
- Speed = Distance ÷ Time →
S = D / T - Distance = Speed × Time →
D = S × T - Time = Distance ÷ Speed →
T = D / S
Variable definitions:
- S = Speed (how fast you are moving, regardless of direction)
- D = Distance (total path length traveled)
- T = Time (duration of travel)
- Velocity = Speed with a direction (e.g., 60 mph north). In everyday problems, speed and velocity are used interchangeably.
Worked example: A car drives 240 miles from New York to Boston. The trip takes 4 hours. Speed = 240 / 4 = 60 mph
Now reverse it: if a train travels at 90 km/h for 2.5 hours: Distance = 90 × 2.5 = 225 km
Unit reference table:
| System | Speed Unit | Distance | Time |
|---|---|---|---|
| Imperial | mph | miles | hours |
| Metric | km/h | kilometers | hours |
| Science | m/s | meters | seconds |
| Maritime | knots | nautical miles | hours |
Conversion quick facts:
- 1 mph = 1.609 km/h
- 1 knot = 1.852 km/h
- 60 mph = 88 feet per second
- Speed of sound at sea level ≈ 767 mph (1,235 km/h)
- Speed of light ≈ 670,616,629 mph (299,792 km/s)
Real-world benchmarks:
- Walking pace: ~3 mph (5 km/h)
- Cycling: ~12–15 mph (19–24 km/h)
- Highway driving: 60–75 mph (97–121 km/h)
- Commercial aircraft: ~575 mph (925 km/h)
This calculator solves for any one of the three values when you provide the other two. Select your preferred unit system, enter the known values, and the result updates instantly.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.